Medical guide wire

ABSTRACT

A medical guide wire includes a flexible long core. A core elongated component is disposed to extend forwards from the core, and has a tapered shape. A helical coil is disposed about the core elongated component, secured by attachment of a coil distal end and a coil proximal end to the core elongated component. The helical coil includes an equiradial coil portion having the coil proximal end, disposed at a portion of the core elongated component on a side of the core. A diameter decreasing coil portion has the coil distal end, extends forwards from the equiradial coil portion, has a decreasing diameter, and has a length 25 mm or more. A diameter ratio D 1 /D 2  of the diameter decreasing coil portion is 1.22-2.31, where D 1  is a proximal end diameter of the diameter decreasing coil portion, and D 2  is a distal end diameter of the diameter decreasing coil portion.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a medical guide wire. Moreparticularly, the present invention relates to a medical guide wire foruse in treatment of blood vessels of constriction, for example acoronary artery, an artery of lower extremities or the like.

2. Description Related to the Prior Art

A medical guide wire is used for inserting a catheter into a bloodvessel for various purposes. A flexible catheter of a very small widthis inserted with the medical guide wire for the purpose of angiographyof vessels. Otherwise, a balloon catheter is inserted in an occlusion ofa coronary artery for intravascular treatment. The use of the medicalguide wire is for safety and reliability. The medical guide wire isrequired to have flexibility and buckling resistant property for thepurpose of insertion in vessels of complicated curved paths or vesselbranches. Also, the medical guide wire should have steerability andsuitable rigidity of torsion in order to operate the guide wire tip in avessel by extracorporeally rotating the proximal end of the medicalguide wire. JP-U 59-016649 and U.S. Pat. No. 5,354,257 (corresponding toJP-A 4-309368) disclose the medical guide wire including a core and ahelical coil. The core has a very small diameter. The helical coil iswound about the core, has a decreasing diameter, so the guide wire tipof the medical guide wire has a tapered shape.

In FIG. 12, a total occlusive lesion 100 in a coronary artery isillustrated. According to gradual organization of thrombus, an occlusion102 in a blood vessel 101 becomes tissue. Organization is rather earlyon ends of the occlusion 102 in contrast with slowness in organizationat the middle point of the occlusion 102. As a result, portions ofplaque or hard tissue 103 occur in the middle path in the blood vessel101. For the total occlusive lesion 100, a medical guide wire 105 forintravascular treatment is used to penetrate the total occlusive lesion100 by rotating forwards and backwards, the medical guide wire 105including a flexible helical coil disposed at the guide wire tip, andhaving strands spaced from one another.

When the guide wire tip of the medical guide wire 105 is rotatedforwards and backwards, a cavity called a false lumen 106 is created ina different direction by drilling of the medical guide wire 105. Thefalse lumen 106 may be enlarged, from which the medical guide wire 105cannot move away. A true lumen cannot be reached as intended in thevessel. In FIG. 13, a recently used method of penetration of the totalocclusive lesion 100 is illustrated. A medical guide wire 110 forintravascular treatment has a rigid tip, and can penetrate the totalocclusive lesion 100 even with the plaque or hard tissue 103 containedin the total occlusive lesion 100. Conception of improving the medicalguide wire 110 has been developed in view of suitability for thismethod. If the rigidity of the guide wire tip is too high, steerabilityof the medical guide wire 110 will be low because of low flexibility ofthe guide wire tip.

In FIG. 14, an encircling calcified lesion 115 is created as a result oforganizing thrombus. Plaque or hard tissue 116 of the calcified lesion115 is still more difficult to penetrate with a tool. There a pair ofends 118 and 119 in a cup shape disposed on the sides of the occlusionof the calcified lesion 115. The end 118 has a greater thickness thanthe end 119. When a medical guide wire 120 for intravascular treatmentpasses through the blood vessel, the guide wire tip buckles in thevicinity of the end 118, which cannot be penetrated. If the medicalguide wire 120 can penetrate, the guide wire tip is likely to offsetfrom the middle of the end 119. The guide wire tip may erroneously reacha false lumen 121, because the middle of the end 119 is convexly formed.No known structure of the guide wire tip can penetrate successfully.

SUMMARY OF THE INVENTION

In view of the foregoing problems, an object of the present invention isto provide a medical guide wire for use in treatment of blood vesselswith high steerable property and also penetrable property.

In order to achieve the above and other objects and advantages of thisinvention, a medical guide wire includes a flexible long core. A coreelongated component is disposed to extend forwards from an end of thecore, and has a tapered shape. A helical coil is disposed about the coreelongated component, secured by attachment of a coil distal end and acoil proximal end to the core elongated component. The helical coilincludes an equiradial coil portion having the coil proximal end,disposed at a portion of the core elongated component on a side of thecore. A diameter decreasing coil portion has the coil distal end, isdisposed to extend forwards from the equiradial coil portion, has adecreasing diameter, and has a length equal to or more than 25 mm. Amiddle connector is disposed at a distance equal to or less than 50 mmfrom the coil distal end, for attaching the helical coil to the coreelongated component. The helical coil has a coil filament with strandstightly wound in a range from the coil distal end to the middleconnector. A diameter ratio D1/D2 of the diameter decreasing coilportion is equal to or more than 1.22 and equal to or less than 2.31,where D1 is a diameter of the diameter decreasing coil portion on a sideof the coil proximal end, and D2 is a diameter of the diameterdecreasing coil portion on a side of the coil distal end. The coreelongated component and the helical coil satisfy a condition of d2≧t,where d2 is a diameter of a distal end of the core elongated component,and t is a filament diameter of the coil filament of the helical coil.

Furthermore, a guide wire tip is positioned at a distal end, and havingone portion of the core elongated component and the coil distal end ofthe helical coil attached to the core elongated component.

The middle connector is positioned on a proximal side from a pointdefined between the diameter decreasing coil portion and the equiradialcoil portion. A first length ratio L1/L2 of the helical coil is equal toor more than 1, where L1 is a length of the diameter decreasing coilportion, and L2 is a length of the equiradial coil portion extending tothe middle connector.

In one preferred embodiment, one end of the diameter decreasing coilportion nearer to the equiradial coil portion is disposed at the middleconnector.

The helical coil further includes an equiradial coil end, disposed toextend forwards from the diameter decreasing coil portion, forconstituting the guide wire tip. A second length ratio L1/L3 of thehelical coil is equal to or more than 3.1 and equal to or less than 24,where L1 is a length of the diameter decreasing coil portion, and L3 isa length of the equiradial coil end.

The second length ratio L1/L3 of the helical coil is equal to or morethan 3.1 and equal to or less than 7.3.

The diameter D1 is equal to or less than 0.360 mm in a range from theguide wire tip to the middle connector. The diameter ratio D1/D2 isequal to or more than 1.22 and equal to or less than 1.85.

In the range from the guide wire tip to the middle connector, thehelical coil and the core elongated component satisfy conditions of:

t≦d2≦(D2−2×t)

t<d1≦(D1−2×t)

1.10≦d1/d2≦2.64.

In the range from the guide wire tip to the middle connector, thehelical coil and the core elongated component satisfy conditions of:

t≦d2≦(D2−2.5×t)

t<d1≦(D1−2.5×t).

In another preferred embodiment, the diameter D1 is equal to or lessthan 0.450 mm in a range from the guide wire tip to the middleconnector. The diameter ratio D1/D2 is equal to or more than 1.52 andequal to or less than 2.31.

In the range from the guide wire tip to the middle connector, thehelical coil and the wire haft satisfy conditions of:

t≦d2≦(D2−2×t)

t<d1≦(D1−2×t)

1.10≦d1/d2≦3.68.

At least the diameter decreasing coil portion in the helical coil isproduced from radiopaque material.

Furthermore, an equiradial helical coil part is secured to theequiradial coil portion of the helical coil, and disposed to extend to aproximal side.

The equiradial helical coil part is attached to the helical coil by themiddle connector.

The helical coil further includes a lubricant coating overlaid on aperipheral surface of at least the diameter decreasing coil portion,having lubricating property when wetted.

In one preferred embodiment, the diameter decreasing coil portion has adiameter decreasing in a range extending to the guide wire tip.

The core elongated component includes an equiradial shaft portiondisposed inside the equiradial coil portion. A tapered shaft portion isdisposed to extend from the equiradial shaft portion and inside thediameter decreasing coil portion, and has a diameter decreasing towardthe guide wire tip.

In still another preferred embodiment, the diameter decreasing coilportion extends toward a proximal side and about the equiradial shaftportion.

In one preferred embodiment, the helical coil includes an equiradialcoil end disposed to extend from the diameter decreasing coil portion tothe guide wire tip. The core elongated component includes an equiradialshaft end disposed to extend from the tapered shaft portion and insidethe equiradial coil end.

The helical coil is so disposed that a space of a predeterminedthickness is defined about the core elongated component in a rangeoffset from the middle connector.

BRIEF DESCRIPTION OF THE DRAWINGS

The above objects and advantages of the present invention will becomemore apparent from the following detailed description when read inconnection with the accompanying drawings, in which:

FIG. 1A is a plan illustrating a core of a medical guide wire;

FIG. 1B is a horizontal section illustrating a core elongated componentand a helical coil of the medical guide wire;

FIG. 2 is an explanatory view in section illustrating each of first,second and third embodiments;

FIG. 3 is a perspective illustrating the first embodiment with indicatedparameters of the guide wire related to transmission of rotation;

FIG. 4A is a schematic view illustrating a state of the guide wirerelated to approach to a lesion in a blood vessel;

FIGS. 4B and 4C are schematic views illustrating a state of the guidewire passing the lesion;

FIG. 5A is a schematic view illustrating a blood vessel and a guide wirefor use in a parallel wire technique;

FIG. 5B is a schematic view illustrating the blood vessel and a set oftwo guide wires in the parallel wire technique;

FIG. 6 is an explanatory view in section illustrating a fourthembodiment in which a middle connector is positioned between a diameterdecreasing coil portion and an equiradial helical coil part;

FIG. 7A is an explanatory view in section illustrating a fifthembodiment in which a tapered shaft portion extends to the guide wiretip;

FIG. 7B is an explanatory view in section illustrating a sixthembodiment in which the middle connector is positioned on a smalldiameter shaft portion;

FIG. 7C is an explanatory view in section illustrating a seventhembodiment with an equiradial shaft end at a very small diameter;

FIG. 8 is an explanatory view in section illustrating an eighthembodiment having a space between the core elongated component and thehelical coil;

FIG. 9 is an explanatory view in section illustrating a ninth embodimenthaving an equiradial coil end;

FIG. 10A is an explanatory view illustrating articulating bends of theguide wire;

FIG. 10B is an explanatory view illustrating articulating bends ofanother preferred guide wire;

FIG. 11 is an explanatory view illustrating a tenth embodiment with ahelical coil coated with a lubricant coating;

FIG. 12 is a schematic view illustrating the use of a known guide wirefor a total occlusive lesion in a coronary artery;

FIG. 13 is a schematic view illustrating the use of the known guide wirefor an occlusive lesion with hard plaque;

FIG. 14 is a schematic view illustrating the use of the known guide wirefor an encircling calcified lesion.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) OF THE PRESENTINVENTION

In FIGS. 1A and 1B, a medical guide wire 10 for intravascular treatmentincludes a core 11, a core elongated component 12 at a distal end, and atubular winding or helical coil 13. The core 11 is long and flexible.The core elongated component 12 extends from a distal end of the core11, and has a smaller diameter in a tapered shape. The helical coil 13is attached to the core elongated component 12. Examples of materialsfor the core 11 are SUS 304 steel, Ni—Ti alloy and the like. Examples ofmaterials for the helical coil 13 are SUS 304 steel, gold, platinum,tungsten or other radiopaque substances. A length of the medical guidewire 10 is 1,400-3,000 mm. A length of the helical coil 13 is 30-300 mm.A proximal end of the core 11 is coated with a covering layer of afluorocarbon resin or the like. An outer periphery of the helical coil13 is coated with a first layer of polyurethane or other resin, and asecond layer of hydrophilic polymer for lubricating property at the timeof being wetted.

A tapered shaft portion 12 a of transition is included in the coreelongated component 12, and has a decreasing diameter. An equiradialshaft end 12 b or ribbon extends from the tapered shaft portion 12 awith a first diameter at a guide wire tip. A small diameter shaftportion 12 c of transition extends from the tapered shaft portion 12 aon the proximal side with a second diameter.

The helical coil 13 includes an equiradial helical coil part 13 d on aproximal side, an equiradial coil portion 13 a on the proximal side, anda diameter decreasing coil portion 13 b of transition. If required, thehelical coil 13 also has an equiradial coil end 13 c at a guide wiretip. The helical coil 13 is set on the core elongated component 12 byreceiving its insertion loosely. The equiradial helical coil part 13 dand the equiradial coil portion 13 a are positioned on the proximal sideof the core elongated component 12. The diameter decreasing coil portion13 b is positioned on the distal side of the core elongated component12. Then the helical coil 13 is fixedly secured to the core elongatedcomponent 12 with paraffin wax. Three positions are determined forfixation with the paraffin wax. A distal end connector 15 at a guidewire tip is located on the distal side of the helical coil 13. Aproximal end connector 16 is located on the proximal side of the helicalcoil 13. A middle connector 17 of paraffin wax similarly is disposedbetween the end connectors 15 and 16.

In the helical coil 13, a coil filament 14 a of alloy is wound toconstitute the equiradial coil end 13 c, the diameter decreasing coilportion 13 b, and a region of the equiradial coil portion 13 a extendingto the middle connector 17, and is produced from alloy containing gold,platinum, tungsten or other radiopaque substance as main component. Thecoil filament 14 a is wound by a spring coil winder known in the art ina tightly wound coil. The helical coil of the coil filament 14 a may bespaced from the core elongated component with a greater diameter, or maybe fitted with the core elongated component at an equal diameter. A coilfilament 14 b is wound to constitute the equiradial helical coil part 13d extending from the middle connector 17 to the proximal side, and isproduced from general-purpose material, such as SUS 304 steel. An amountof radiopaque substances is reduced by the combined use of the steel orthe like, to reduce the manufacturing cost, while radiopaque substancesare typically expensive. The middle connector 17 attaches the coilfilament 14 b to the coil filament 14 a with paraffin wax. At least oneturn of the coil filament 14 b is helically coupled with at least oneturn of the coil filament 14 a at the middle connector 17 beforeattachment with the paraffin wax. Note that the coil filament 14 b inthe helical coil 13 can be different from the coil filament 14 a in thefilament diameter in place of the material. Various methods areavailable to produce the helical coil 13. For example, a first wire ofradiopaque material is attached by welding to a second wire of aradiolucent material. The first and second wires are then coiled to formthe helical coil 13. Otherwise, a wire of a single material can be woundin a coiled form. Irrespective of the methods, however, it is importantto keep the helical coil 13 tightly attached by the middle connector 17at a predetermined distance.

Note that a meaning of the term of tight winding in this specificationincludes a state of complete contact of all strands of the coil filament14 a wound in the helical coil 13, and also a state of apparently tightcontact of strands of the coil filament 14 a as viewed by human eyes.Strands of the coil filament 14 a contacting one another as viewed byhuman eyes may be separate from one another if observed in enlargementwith a lens or the like. The term of the tight winding in thisspecification is also used to include a state of existence of a spacebetween strands of the coil filament 14 a equal to or less than 9%relative to the filament diameter t1 (mm) of the coil filament 14 a.Note that the space between strands of the coil filament 14 a can bepreferably equal to or less than 5% relative to the filament diameter t1(mm) of the coil filament 14 a, and equal to or less than 3%.

As important features of the helical coil 13, the diameter decreasingcoil portion 13 b is included. A portion extending to the middleconnector 17 is formed from a radiopaque material. Note that theentirety of the coil filament 14 a may be produced from a radiopaquematerial according to the invention. However, the partial use of theradiopaque material for portions including the diameter decreasing coilportion 13 b is advantageous, because the cost of manufacturing isreduced in consideration of the expensive radiopaque material.

Various preferred embodiments with the core elongated component 12, thehelical coil 13 and other portions are hereinafter described. In FIG. 2,a first embodiment is illustrated. The coil filament 14 a of platinumhas a filament diameter t1 of 0.065 mm, and is wound to define thediameter decreasing coil portion 13 b and the equiradial coil portion 13a of the helical coil 13. The coil filament 14 b of SUS 304 steel has afilament diameter t2 of 0.060 mm, and is wound by coiling to define theequiradial helical coil part 13 d of the helical coil 13 from the middleconnector 17 to the proximal side. The equiradial helical coil part 13 dis attached to the equiradial coil portion 13 a by the middle connector17 with paraffin wax to obtain the helical coil 13. Note that theequiradial helical coil part 13 d on the proximal side may not be woundtightly with a difference from the diameter decreasing coil portion 13b. The proximal end diameter D1 of the helical coil 13 is equal to orless than 0.360 mm. The tapered portion length L1 of the diameterdecreasing coil portion 13 b is equal to or more than 25 mm. A diameterratio D1/D2 of the proximal end diameter D1 to the diameter D2 is equalto or more than 1.22 and equal to or less than 1.85. The length L0 fromthe guide wire tip to the middle connector 17 is 50 mm.

The core elongated component 12 has the distal shaft diameter d2 that isequal to or more than filament diameter t1 of the coil filament 14 a,and is shaped with a decreasing diameter in a tapered manner. The firstembodiment is constructed as a guide wire for treatment of a coronaryartery. Second to tenth embodiments following the first embodiment aredisclosed for this common purpose. The diameter of the medical guidewire 10 is extremely small in comparison with its length. Note that themedical guide wire 10 can be hardly depicted in one drawing sheet if aratio of enlargement is the same in the longitudinal direction as in theradial direction. So the medical guide wire 10 is depicted in a higherfactor of enlargement in the radial direction than in the longitudinaldirection.

In the first embodiment having the tapered end portion with tightlywound strands of the helical coil 13, the diameter decreasing coilportion 13 b can cause performance of transmission to be higher from theproximal side to the distal side, and also can raise force ofpenetration or advance. In FIG. 3, torque or rotational force T1 and T2for the helical coil 13 is determined according to a length ratio r1/r2of lengths or radii of rotatable portions. As the diameter D1 is 0.360mm and the diameter D2 is 0.253 mm, rotational transmission of forcefrom the proximal side to the distal side is approximately 1.42 timeshigher than an example in a regularly helical shape having D1 and D2 of0.360 mm, because of 0.360/0.253.

The operation of the helical coil 13 is assumed in a form of a screw.Force P in the axial direction is proportional to a force in thetangential direction. The tangential force is regarded as torsionalforce. The torsional force of the helical coil 13 is approximately 1.42times as high as that of a helical coil of which D1 and D2 is 0.360 mmequally. The axial direction force P can be approximately 1.42 timeshigher. Therefore, ability of penetration can be high with higherperformance of transmission of rotation and higher force in the axialdirection. High force of penetration is obtained for any of lesions,including a total occlusive lesion 100 of FIG. 12, and a calcifiedlesion 115 and ends 118 and 119 of the calcified lesion 115 in a cupshape illustrated in FIG. 14.

Spring constants of a fully equiradial helical coil and the helical coil13 having an equal filament diameter are calculated. As a result, aspring constant of the helical coil 13 is approximately 1.59 times asmuch as that of the fully equiradial helical coil having the equalfilament diameter and having a maximum coil diameter equal betweenthose. Note that a torsion angle of a coil changes inverselyproportional to the spring constant. Thus, a torsion angle of thehelical coil 13 is small. Therefore, rotational force on the proximalside can be transmitted to the distal side with a high rotational forceeven with a rotation at a small torsion angle. It is possible in FIGS.4A-4C that a constriction 30 can be penetrated by the guide wire.

FIGS. 4A-4C illustrate a state of a guide wire tip 105 a in theconstriction 30 according to a known medical guide wire 105 forintravascular treatment. For example, a blood vessel 32 has theconstriction 30. One vessel wall 32 a has a large plaque or hardprotrusion 33. A second vessel wall 32 b has a small plaque or hardprotrusion 34, which defines the constriction 30 with the large plaque33. In FIG. 4B, an inclined surface 33 a of the large plaque 33 ispressed by the guide wire tip 105 a of the medical guide wire 105, whichcauses deflection, and is slightly moved back while rotated. In FIG. 4C,the guide wire tip 105 a is caused to penetrate the constriction 30 byuse of the reaction force of the guide wire tip 105 a as a spring.

In FIG. 4B, failure of penetration of the medical guide wire 105 isillustrated. Upon contact with the inclined surface 33 a, the guide wiretip 105 a becomes buckled due to the bendable property. Spaces betweenstrands of the coil of the medical guide wire 105 are enlarged byparticles of plaque, so reaction force of the guide wire tip 105 adecreases considerably. Thrusting into the constriction 30 with thereaction force may be unsuccessful.

The helical coil 13 according to the first embodiment has a shape ofwhich the diameter of the distal end decreases in a tapered manner.There is no space between strands owing to the tight winding of the coilfilament 14 a. Thus, the helical coil 13 can have a high spring constantin comparison with the regular diameter coil spring of which the maximumdiameter is the same as that of the helical coil 13. Sufficient reactionforce can be ensured by the high spring constant. No gap between thestrands will open according to the tight winding, hard pieces of plaqueare prevented from entry in or interference with a portion of the coilfilament 14 a. The shape of the reduced diameter of the distal end isalso effective in passage through the constriction 30 by means of thereaction force of the spring.

There is a method referred to as a parallel wire technique of medicalguide wires 41 and 42 for intravascular treatment. In FIGS. 5A and 5B,the medical guide wire 41 is inserted in a coronary artery 45. Then themedical guide wire 42 is inserted into the coronary artery 45 by use ofthe medical guide wire 41 as a guide. A lesion 43 in the coronary artery45 is penetrated by the medical guide wire 42. A guide wire of theinvention can be effectively used as the medical guide wire 42 in usefor the second time. It is possible easily to penetrate the lesion 43,specifically a diffuse lesion having a lesion length of 20 mm or more,and a right coronary artery having a bend of a zigzag shape.

In FIG. 5A, the medical guide wire 41 is inserted in a blood vesselbranch 44, to extend the coronary artery 45 of a bent shape in astraightened manner. See FIG. 5B. Then the medical guide wire 42 of asecond insertion is introduced to the lesion 43 while guided by themedical guide wire 41. As described above, a farther end 46 in a cupshape of the occlusion has a convex shape at the center. Failure islikely to occur with the known guide wire in accessing the middle of thefarther end 46, because the guide wire has a soft guide wire tip.Furthermore, a loosely wound helical coil with spaces between strandshas a problems in incidental entanglement of the medical guide wire 42with the medical guide wire 41.

In contrast, the first embodiment has the tapered distal portion, and asmall diameter at the guide wire tip. For the penetrability uponhandling on the proximal side, a surface pressure of the guide wire tipper unit area of the end surface increases, so performance ofpenetration is high. The small diameter of the guide wire tip ispredetermined according to the filament diameter. Penetration andbreakage of the plaque can be efficient and easy. Also, the coilfilament 14 a in the helical coil 13 is wound with tightly woundstrands. Entanglement of the medical guide wire 42 with the medicalguide wire 41 can be prevented. Even when a perforation of the vesseloccurs, the perforation diameter can be small because of the smalldiameter of the guide wire tip. The hemostasis is easy in comparisonwith the state of using the structure having fully equiradial helicalcoil.

The middle connector 17 with paraffin wax is positioned at a distance of50 mm or less from the guide wire tip. The length of the diameterdecreasing coil portion 13 b of the helical coil 13 is set equal to ormore than a half of a length from the distal end to the middle connector17. Thus, attachment of the core 11 to the helical coil 13 with paraffinwax is combined with the tightly wound state of the helical coil 13. Itis possible as an effect to prevent widening intervals between the coilfilament 14 a of the helical coil 13 owing to the middle connector 17even when the tip of the medical guide wire 10 penetrates into a lesionwith hard plaque or tissue. Transmission of rotation toward the guidewire tip can be ensured to raise the performance of penetration, becausethe middle connector 17 and the distal end connector 15 firmly attachthe core elongated component 12 to the helical coil 13 at a smalldistance to the guide wire tip.

As the distal shaft diameter d2 is determined equal to or greater than adiameter of the coil filament 14 a, the strength can be kept withoutlowering. Specifically, the minimum diameter of the turns of the helicalcoil 13 is equal to or less than three (3) times as much as the diameterof the coil filament 14 a. Should the minimum diameter be still smaller,tensile stress occurs at points of the outer side of turns, because thelength ratio of the coil filament 14 a increases between the inner sideand the outer side. A surface of strands of the helical coil 13 will beroughened in a scale shape. The helical coil 13 may break or damageaccording to insufficient strength.

As the tapered portion length L1 of the diameter decreasing coil portion13 b of the helical coil 13 is equal to or more than 25 mm, the helicalcoil 13 can be suitable for treatment of a diffuse lesion in a bloodvessel. In contrast with the length of 10-15 mm of a lesion of a generaltype, a length of the diffuse lesion is very likely to be 20 mm or more.Should the tapered portion length L1 of the diameter decreasing coilportion 13 b be smaller than 25 mm, the equiradial portion on theproximal side may jam in a lesion of the hard material or plaque. Thevalue of 25 mm for the tapered portion length L1 is for sufficiency ofthe length in view of suitability for the diffuse lesion.

In FIG. 2, the tapered portion length L1 of the helical coil 13 is 25mm. The length L0 from the guide wire tip to the middle connector 17 is50 mm. Rotational transmission of force from the proximal side to thedistal side is approximately 1.29 times higher than an example in afully equiradial helical shape. Thus, the force can be rotationallytransmitted with higher efficiency. A torsion angle of the helical coil13, which changes inversely proportional to the spring constant, can bereduced in the invention. The rotational force can be transmitted to theguide wire tip only with a small force or small angle rotationally.Performance of penetration can be high.

The distal end diameter D2 of the helical coil 13 is three (3) or moretimes as much as the filament diameter t1 of the coil filament 14 a forthe purpose of preventing roughening of the surface and lowering of thestrength. For example, the filament diameter t1 of the coil filament 14a is 0.065 mm. The diameter d2 of the core elongated component 12 is0.065 mm. The distal end diameter D2 of the helical coil 13 is 0.195 mm.A surface pressure of a guide wire tip 19 per unit area of the endsurface decreases when the distal end diameter D2 becomes more than0.295 mm, so performance of penetration becomes lower. As the medicalguide wire 10 is used in a catheter as a guiding tool for a ballooncatheter, an inner diameter of the medical guide wire 10 is 0.360 mm fortreatment of the coronary artery under the condition limited by theinner diameter of the catheter. Thus, the diameter ratio D1/D2 of thediameter decreasing portion is determined equal to or more than 1.22(=0.360/0.295) and equal to or less than 1.85 (=0.360/0.195), to obtainhigher performance of penetration without lowering the strength.

In FIG. 2, a second embodiment is illustrated. The first embodiment isrepeated with a difference in that a tapered portion length L1 of thehelical coil 13 is 32 mm. A length L2 of a region of the equiradial coilportion 13 a extending to the middle connector 17 is 18 mm. A thirdembodiment is also constructed. The second embodiment is repeated with adifference in that the length L2 is 6 mm.

As the length L2 is 18 mm, a spring constant is approximately 1.37 timesas high as that of a helical coil of a fully equiradial form. Incontrast with the first embodiment having the ratio L1/L2=1/1 betweenthe diameter decreasing coil portion 13 b and the equiradial coilportion 13 a, the second embodiment has a ratio L1/L2=1/1.7. The springconstant increases owing to the increase in the tapered portion lengthL1.

In the third embodiment, as the length L2 is 6 mm, a spring constant isapproximately 1.5 times as high as that of a helical coil of a fullyequiradial form. The torsion angle and the spring deflection decreasebecause the spring constant increases. Also, the middle connector 17 isattached to the equiradial coil portion 13 a. There is no point ofattachment to the diameter decreasing coil portion 13 b being inclined.No unwanted flow of paraffin wax occurs on the diameter decreasing coilportion 13 b. So operation of dispensing paraffin wax can be carried outstably. Furthermore, strength of attachment with the core elongatedcomponent can be kept from lowering, because flowing away of paraffinwax is prevented.

A fourth embodiment is illustrated in FIG. 6. The first embodiment isrepeated with a difference in that the equiradial coil portion 13 a,which is positioned near to a proximal end of the diameter decreasingcoil portion 13 b having its greatest diameter, is associated with themiddle connector 17 with paraffin wax. L2=0 mm. The tapered portionlength L1 is equal to or more than 25 mm and equal to or less than 50mm. The position of attachment with the paraffin wax is effective inobtaining a highest spring constant, and reducing the torsional angleand an spring deflection. No equiradial portion exists in the helicalcoil 13 from the guide wire tip to the middle connector as the diameterdecreasing coil portion 13 b extends at the full length. A springconstant is approximately 1.59 times as high as that of a helical coilof a fully equiradial form. The spring constant of the embodiment is thehighest among all of the embodiments herein. As has been describedabove, the torsional angle and the spring deflection are inverselyproportional. When spring constant increases, the torsional angle andthe spring deflection decrease. Note that the spring constant isdetermined according to an equation for a relationship between thespring constant and spring deflection, and a formula for determiningspring deflection of fully equiradial helical coil springs and conicalcoil springs.

In FIGS. 7A-7C, fifth, sixth and seventh embodiments are illustrated.The fourth embodiment is repeated with a difference of a tapered shapeof the core elongated component 12. A portion of the core elongatedcomponent 12 positioned inside the diameter decreasing coil portion 13 bof the helical coil 13 is tapered, to raise performance of rotationalforce to the guide wire tip. This is because the diameter of the coreelongated component 12 can be great to extend to the inner diameter of aproximal end of the diameter decreasing coil portion 13 b of the helicalcoil 13. Also, rotational transmission depends upon a length ratiobetween lengths or radii of radial portions.

Specifically, the distal end diameter D2 of the helical coil 13 is 0.253mm. The distal shaft diameter d2 of the core elongated component 12 is0.123 mm as the filament diameter t1 of the helical coil 13 is 0.065 mm.As the diameter D1 of the proximal side of the helical coil 13 is 0.360mm, the proximal shaft diameter d1 of the core elongated component 12 isat most 0.230 mm. Rotational transmission of force from the proximalside to the distal side is approximately 1.87 times higher than anexample in a regularly helical shape having the distal shaft diameter d2of 0.253 mm in the core elongated component 12 because of 0.230/0.123.Thus, the force can be rotationally transmitted with higher efficiency.

A preferable range of the ratio d1/d2 of the tapered shaft portion 12 aof the core elongated component 12 is from 1.10 to 2.64 in considerationof stability of the coil form, distal end strength, and high performanceof rotational transmission. Specifically, the diameter of the core onthe side of the proximal end connector 16 is 0.135 mm for the purpose ofkeeping rotational transmission and considering the flowing property ofparaffin wax. The distal end diameter of the core elongated component isat most 0.123 mm (=0.253−0.065×2). The diameter ratio between the coreportions is approximately 1.10. The diameter d2 of the equiradial shaftend 12 b of the core elongated component 12 is 0.087 mm for the purposeof keeping stability of the coil form and strength of the core elongatedcomponent 12. The proximal shaft diameter d1 of the core elongatedcomponent 12 at the proximal end connector 16 is 0.230 mm(=0.360−0.065×2) or less. The diameter ratio d1/d2 is approximately 2.64(=0.230/0.087). Note that the tapered shaft portion 12 a can be shapedwith a length corresponding to the diameter decreasing coil portion 13 bof the helical coil 13 in the manner of FIG. 7A of the fifth embodiment.Also, the tapered shaft portion 12 a of the core elongated component 12can be formed shorter than the diameter decreasing coil portion 13 b ofthe helical coil 13 in the manners of FIGS. 7B and 7C of the sixth andseventh embodiments, to facilitate insertion of the core elongatedcomponent 12 into the helical coil 13.

An eighth embodiment is illustrated in FIG. 8. The fourth embodiment isrepeated with a difference in that a space C (=C1×2) is formed betweenthe core elongated component 12 and the helical coil 13. The space C atthe middle connector 17 of the helical coil 13 on the core elongatedcomponent 12 is ½ as much as the filament diameter t1 of the coilfilament 14 a.

In the eighth embodiment, a predetermined space C1 is defined betweenthe core elongated component 12 and the helical coil 13, so intensity ofattachment with the core elongated component 12 is ensured by higherflowability of paraffin wax into the space. The insertion of the coreelongated component 12 into the helical coil 13 is facilitated to raisesuitability for assembly. Performance of transmission of rotation to thecore elongated component 12 can be high according to the highflowability and suitability for assembly. The distal end diameter D2 ofthe helical coil 13 is 0.253 mm. The filament diameter t1 of the helicalcoil 13 is 0.065 mm. Thus, the distal shaft diameter d2 is 0.0905 mm. Asthe proximal end diameter D1 of the helical coil 13 is 0.360 mm, and theproximal shaft diameter d1 of the core elongated component 12 is 0.1975mm, rotational transmission of force from the proximal side to thedistal side is approximately 2.18 times higher than an example in aregularly helical shape, because of 0.1975/0.0905.

The diameter ratio d1/d2 is equal to or more than 1.10 and equal to orless than 2.36. Thus, the stability of the helical shape can be keptwith the strength of the tip of the core elongated component accordingto the fourth embodiment. Furthermore, performance of transmission ofrotation can be higher in a similar manner to the coil spring taperedportion. Note that the diameter ratio d1/d2 is preferably equal to ormore than 1.49 and equal to or less than 2.27 as a preferable range. Thereason for this is described as follows.

In consideration of the rotational transmission to the distal end, theproximal shaft diameter d1 is 0.135 mm. The distal shaft diameter d2 is0.0905 mm (=0.253−0.065×2.5). The diameter ratio d1/d2 is approximately1.49 (=0.135/0.0905). In consideration of the stability of the coilshape and strength of the guide wire tip, the distal shaft diameter d2is 0.087 mm. The proximal shaft diameter d1 of the proximal endconnector 16 is 0.1975 (=0.360−0.065×2.5). The diameter ratio d1/d2 isapproximately 2.27 (=0.1975/0.087). Thus, the diameter ratio d1/d2 ispreferably equal to or more than 1.49 and equal to or less than 2.27.

Note that in the calculation, the factor of 2.5 is derived from acombination of two times the filament diameter of the coil filament 14 aand the thickness of the space C.

A ninth embodiment is illustrated in FIG. 9. The eighth embodiment isrepeated with a difference in that the equiradial coil end 13 c isdisposed as distal end of the helical coil 13. The equiradial coil end13 c has a diameter equal to the first diameter D2 of the diameterdecreasing coil portion 13 b on the distal side. A ratio L1/L3 of thetapered portion length L1 to the equiradial portion length L3 is equalto or more than 3.1 and equal to or less than 7.3.

Thus, the steerable property can be higher to reach a true lumen of alesion of the vessel, as the equiradial coil end 13 c is additionallydisposed on the diameter decreasing coil portion 13 b. In general, aplurality of guide wires are prepared and used for selective purposes oftypes of blood vessels. For example, guide wire tips are curved. Also,in FIGS. 10A and 10B, articulating bends 50 a, 50 b, 51 a and 51 b areprovided in guide wires, and have two bent forms. When medical guidewires 50 and 51, having a guide wire tip with high rigidity, is used inthe above-described parallel guide wire technique for a total occlusionin intravascular treatment, the medical guide wire 51 is constructedwith a different guide wire tip from that of the medical guide wire 50.This is effective in reaching a true lumen by guiding the tip of themedical guide wire 51 in a direction different from the medical guidewire 50. Specific parameters are changed for the state of lesions,including an angle θ1 defined between the articulating bends 50 a and 50b, an angle θ3 defined between the articulating bends 51 a and 51 b, anangle θ2 defined between the articulating bend 50 b and a guide wirebody 50 c, and an angle θ4 defined between the articulating bend 51 band a guide wire body 51 c, and lengths LB1-LB4 of the bends. Forexample, θ1 is 45 degrees, θ2 is 15 degrees, θ3 is 45 degrees, θ4 is 30degrees, LB1 is 2 mm, LB2 is 4 mm, LB3 is 2 mm and LB4 is 6 mm. Also,the total length LB5 (=LB1+LB2 or LB3+LB4) is equal to or less than 8mm. A micro catheter is extended to each of points of bends particularlyfor the structure with the two bends. Shapes of the bends are selectedfor use in the treatment of blood vessels.

In relation to constructing the articulating bends 50 a and 50 b or thearticulating bends 51 a and 51 b, the tendency of bending can be easilyimparted if a shape of a region of bending is equiradial. If the shapeof a bending region is tapered, rigidity changes gradually at each ofpoints of bending, so that a difficulty is higher in determining thebending position in comparison with the equiradial shape. A length ratiobetween the equiradial coil end 13 c and the diameter decreasing coilportion 13 b is equal to or more than 3.1 and equal to or less than 7.3.Specifically, when the equiradial portion length L3 of the equiradialcoil end 13 c is 8 mm, the minimum size of the tapered portion is 25 mm.A ratio L1/L3 is 25/8=3.1. As the equiradial portion length L3 is 6 mm,the tapered portion length L1 is 44 mm. A ratio L1/L3 between those is44/6=7.3. Thus, it is preferable that the ratio L1/L3 between thediameter decreasing coil portion 13 b and the equiradial coil end 13 cis equal to or more than 3.1 and equal to or less than 7.3. Theequiradial coil end 13 c is effective in ensuring the flexibility of theguide wire tip, because the region of the small diameter is keptsufficient by the equiradial coil end 13 c in comparison with thetotally tapered structure.

In FIG. 11, a tenth embodiment is illustrated. The ninth embodiment isrepeated with a difference in that a lubricant coating 60 is applied onthe peripheral surface of the helical coil 13. Characteristically, thelubricant coating 60 comes to have lubricating property when wetted. Ahydrophobic coating layer 61 is formed on the outer surface of thehelical coil 13. After this, a coating layer 62 of hydrophilic polymeris formed on the hydrophobic coating layer 61. The hydrophobic coatinglayer 61 and the hydrophilic coating layer 62 are combined to constitutethe lubricant coating 60. As the helical coil 13 is tightly wound, thehydrophobic material does not enter the space between strands of thehelical coil 13 even in application of the coating of the hydrophobicmaterial. The hydrophobic material can coat the surface of the helicalcoil 13 in a sufficiently smooth manner. Then a coating of thehydrophilic polymer is applied to the hydrophobic coating layer 61, toform the hydrophilic coating layer 62. The double structure of thecoating layers makes the outer surface smooth. High smoothness can beobtained in comparison with loosely wound helical coils. Examples of thehydrophobic materials include polyurethane, polyamide, fluorocarbonresin and the like. Examples of hydrophilic materials include polyvinylpyrolidone, polyethylene oxide, anhydride of maleic acid ethyl ester,and the like.

An eleventh embodiment is described now. The first embodiment of FIG. 2is repeated with a difference in that the diameter D1 of the helicalcoil 13 on the proximal side is 0.450 mm or less, and that the ratioD1/D2 between the diameters D1 and D2 on the proximal and distal sidesis equal to or more than 1.52 and equal to or less than 2.31. Theeleventh embodiment is constructed as a guide wire for treatment ofblood vessels in lower extremities. The eleventh, twelfth and thirteenthembodiments are disclosed for this common purpose.

There is a reason of enlarging the diameter D1 of the helical coil 13.To introduce a treatment tool into the lesion of an occlusion of avessel of lower extremities, it is preferable to insert the tool throughan upper thigh near to the lesion. However, there is a problem inrequiring long time for hemostasis of blood because of the greatdiameter of the vessel of the lesion. Ischemia is likely to occur.Another technique of treatment is to approach the lower extremitiesthrough an arm. A treatment tool is introduced through the arm, passedthrough the arch of aorta and then an abdominal aorta to reach theocclusion of a peripheral artery of the lower extremities for treatment.It is necessary for a treatment tool to have flexibility for passagethrough the arch of aorta with a long path, and penetrability sufficientfor reaching a target lesion.

In general, a vessel diameter of a lesion in the vessels of lowerextremities is relatively greater than a vessel diameter of a lesion ofthe coronary artery. A length of the occlusion at the lesion in thevessels of lower extremities is also greater than that of the coronaryartery. To be precise, the vessel diameter of the coronary artery is 2-3mm. The vessel diameter of the lesion in the vessels of lowerextremities is 4-6 mm in regions higher than the knee joint, and 2-4 mmin regions lower than the knee joint. There are some exceptionsaccording to specificity and differences between portions of lesions. Alength of a diffuse lesion is 20 mm at the lesion of the coronaryartery, but is 100 mm or more at the lesion in the vessels of lowerextremities. Variants may exist according to specificity and differencesbetween portions of lesions.

Therefore, a guide wire should be constructed by considering a path toapproach a lesion, vessel diameter, and lesion length. The guide wirefor lower extremities requires penetrability, and should have a greaterdiameter than that for treatment of a coronary artery.

The diameter of the helical coil 13 is equal to or less than 0.450 mm.The ratio D1/D2 is in a range of 1.52-2.31. This is because the proximalshaft diameter d1 of the core elongated component 12 in the helical coil13 can be greater by raising the diameter D1 of the helical coil 13 onthe proximal side. As the diameter D1 rises from the 0.360 mm to the0.450 mm, the diameter of the core elongated component 12 can be greaterin association with this. The flexural rigidity can be approximately 2.4times higher because the flexural rigidity is proportional to thegeometrical moment of inertia. Thus, the suitability for penetration canbe better.

When the diameter D2 is more than 0.295 mm, a surface pressure of theguide wire tip 19 per unit area becomes lower to lower the penetratingproperty. For use with a balloon catheter, the medical guide wire 10 inthe balloon catheter of a widely manufactured type has the maximumdiameter of 0.450 mm. Thus, the diameter ratio D1/D2 is equal to or morethan 1.52 (=0.450/0.295) and equal to or less than 2.31 (=0.450/0.195).As an important feature of the invention, the diameter ratio D1/D2 isequal to or more than 1.22 and equal to or less than 2.31, as a resultof combining the first embodiment with the diameter ratio D1/D2 of1.22-1.85, and the eleventh embodiment with the diameter ratio D1/D2 of1.52-2.31.

The medical guide wire 10 for vessels of lower extremities requiresflexibility and penetrability. The flexibility is suitability forpassing the arch of aorta with a large bend even after percutaneouslyintroducing through an artery of an arm, the penetrability beingsuitability for passing the arch of aorta and then the abdominal aortato reach a target region of the peripheral artery to be treated. Afterthe reach to the peripheral artery, high performance of penetration canbe obtained according to the tapered shape of the helical coil.

A twelfth embodiment is constructed. The eleventh embodiment is repeatedwith a difference of the diameter ratio D1/D2 equal to or more than 1.52and equal to or less than 2.31. Also, the diameter ratio d1/d2 of thecore elongated component 12 is equal to or more than 1.10 and equal toor less than 3.68. This is based on the same reason as the fourthembodiment. The diameter of the helical coil is considered.

d1/d2=0.135/(0.253−0.065×2)=1.10; and

d1/d2=(0.450−0.065×2)/0.087=3.68

A thirteenth embodiment is described now. The eleventh embodiment isrepeated with a difference in that the equiradial coil end 13 c ispositioned on the distal side of the diameter decreasing coil portion 13b of the helical coil 13. A ratio L1/L3 of the tapered portion length L1to the equiradial portion length L3 is equal to or more than 3.1 andequal to or less than 24. Specifically, the minimum value of the taperedportion length L1 is 25 mm when the equiradial portion length L3 is 8mm. The ratio L1/L3 between those is 3.1 (=25/8). Also, the maximumvalue of the tapered portion length L1 is 48 mm when the equiradialportion length L3 is 2 mm. The ratio L1/L3 between those is 24 (=48/2).Accordingly, it is preferable in the invention that the ratio L1/L3 is3.1-24 because of a range of 2-8 mm of the equiradial portion length L3.

The equiradial coil end 13 c is disposed on the diameter decreasing coilportion 13 b. The length ratio L1/L3 of the helical coil 13 is equal toor more than 3.1 and equal to or less than 7.3. The tapered portionlength L1 of the diameter decreasing coil portion 13 b is 25 mm as theequiradial portion length L3 is 8 mm. The length ratio L1/L3 is 3.1(=25/8). Further, the tapered portion length L1 of the diameterdecreasing coil portion 13 b is at least 44 mm as the equiradial portionlength L3 is 6 mm. The length ratio L1/L3 is 7.3 (=44/6). Accordingly,the length ratio L1/L3 is equal to or more than 3.1 and equal to or lessthan 7.3. The present example can have a higher flexibility of the guidewire tip than the structure in a fully tapered shape, because the smalldiameter portion is defined by the equiradial coil end 13 c with asufficient length. Note that it is possible for an operator to selectone of the twelfth and thirteenth embodiments according to an observedstate of a lesion. In a similar manner to the tenth embodiment, it ispreferable in the eleventh, twelfth and thirteenth embodiments to applythe lubricant coating 60 on the periphery of the helical coil 13 in aregion extending to the proximal connector for the lubricating propertywhen wetted.

In the above embodiment, the helical coil 13 is the monofilament helicalcoil of which a single filament is wound. However, the helical coil 13may be the plural filament helical coil in which plural filaments arewound in a coil form. In the plural filament helical coil, diameters ofthe plural filaments may be equal to one another, or can be differencefrom one another. The use of the plural filaments in the plural filamenthelical coil is effective in having a high tensile strength and highersafety. Also, a shape with a recess or protrusion in the plural filamenthelical coil makes it possible to impart high performance of penetrationto the helical coil 13.

Although the present invention has been fully described by way of thepreferred embodiments thereof with reference to the accompanyingdrawings, various changes and modifications will be apparent to thosehaving skill in this field. Therefore, unless otherwise these changesand modifications depart from the scope of the present invention, theyshould be construed as included therein.

1. A medical guide wire comprising: a flexible long core; a coreelongated component, disposed to extend forwards from an end of saidcore, having a tapered shape; a helical coil, disposed about said coreelongated component, secured by attachment of a coil distal end and acoil proximal end to said core elongated component; said helical coilincluding: an equiradial coil portion, having said coil proximal end,disposed at a portion of said core elongated component on a side of saidcore; a diameter decreasing coil portion, having said coil distal end,disposed to extend forwards from said equiradial coil portion, having adecreasing diameter, and having a length equal to or more than 25 mm; amiddle connector, disposed at a distance equal to or less than 50 mmfrom said coil distal end, for attaching said helical coil to said coreelongated component; wherein said helical coil has a coil filament withstrands tightly wound in a range from said coil distal end to saidmiddle connector; a diameter ratio D1/D2 of said diameter decreasingcoil portion is equal to or more than 1.22 and equal to or less than2.31, where D1 is a diameter of said diameter decreasing coil portion ona side of said coil proximal end, and D2 is a diameter of said diameterdecreasing coil portion on a side of said coil distal end; said coreelongated component and said helical coil satisfy a condition of d2≧t,where d2 is a diameter of a distal end of said core elongated component,and t is a filament diameter of said coil filament.
 2. A medical guidewire as defined in claim 1, further comprising a guide wire tip,positioned at a distal end, and having one portion of said coreelongated component and said coil distal end of said helical coilattached to said core elongated component.
 3. A medical guide wire asdefined in claim 2, wherein said middle connector is positioned on aproximal side from a point defined between said diameter decreasing coilportion and said equiradial coil portion; a first length ratio L1/L2 ofsaid helical coil is equal to or more than 1, where L1 is a length ofsaid diameter decreasing coil portion, and L2 is a length of saidequiradial coil portion extending to said middle connector.
 4. A medicalguide wire as defined in claim 2, wherein one end of said diameterdecreasing coil portion nearer to said equiradial coil portion isdisposed at said middle connector.
 5. A medical guide wire as defined inclaim 2, wherein said helical coil further includes an equiradial coilend, disposed to extend forwards from said diameter decreasing coilportion, for constituting said guide wire tip; a second length ratioL1/L3 of said helical coil is equal to or more than 3.1 and equal to orless than 24, where L1 is a length of said diameter decreasing coilportion, and L3 is a length of said equiradial coil end.
 6. A medicalguide wire as defined in claim 5, wherein said second length ratio L1/L3of said helical coil is equal to or more than 3.1 and equal to or lessthan 7.3.
 7. A medical guide wire as defined in claim 2, wherein saiddiameter D1 is equal to or less than 0.360 mm in a range from said guidewire tip to said middle connector; said diameter ratio D1/D2 is equal toor more than 1.22 and equal to or less than 1.85.
 8. A medical guidewire as defined in claim 7, wherein in said range from said guide wiretip to said middle connector, said helical coil and said core elongatedcomponent satisfy conditions of:T≦d2≦(D2−2×t)t<d1≦(D1−2×t)1.10≦d1/d2≦2.64.
 9. A medical guide wire as defined in claim 7, whereinin said range from said guide wire tip to said middle connector, saidhelical coil and said core elongated component satisfy conditions of:t≦d2≦(D2−2.5×t)t<d1≦(D1−2.5×t).
 10. A medical guide wire as defined in claim 2, whereinsaid diameter D1 is equal to or less than 0.450 mm in a range from saidguide wire tip to said middle connector; said diameter ratio D1/D2 isequal to or more than 1.52 and equal to or less than 2.31.
 11. A medicalguide wire as defined in claim 10, wherein in said range from said guidewire tip to said middle connector, said helical coil and said coreelongated component satisfy conditions of:t≦d2≦(D2−2×t)t<d1≦(D1−2×t)1.10≦d1/d2≦3.68.
 12. A medical guide wire as defined in claim 10,wherein in said range from said guide wire tip to said middle connector,said helical coil and said core elongated component satisfy conditionsof:t≦d2≦(D2−2.5×t)t<d1≦(D1−2.5×t).
 13. A medical guide wire as defined in claim 2, whereinat least said diameter decreasing coil portion in said helical coil isproduced from radiopaque material.
 14. A medical guide wire as definedin claim 13, further comprising an equiradial helical coil part, securedto said equiradial coil portion of said helical coil, and disposed toextend to a proximal side.
 15. A medical guide wire as defined in claim14, wherein said equiradial helical coil part is attached to saidequiradial coil portion by said middle connector.
 16. A medical guidewire as defined in claim 2, wherein said helical coil further includes alubricant coating, overlaid on a peripheral surface of at least saiddiameter decreasing coil portion, having lubricating property whenwetted.
 17. A medical guide wire as defined in claim 2, wherein saiddiameter decreasing coil portion has a diameter decreasing in a rangeextending to said guide wire tip.
 18. A medical guide wire as defined inclaim 2, wherein said core elongated component includes: an equiradialshaft portion disposed inside said equiradial coil portion; a taperedshaft portion, disposed to extend from said equiradial shaft portion andinside said diameter decreasing coil portion, and having a diameterdecreasing toward said guide wire tip.
 19. A medical guide wire asdefined in claim 18, wherein said diameter decreasing coil portionextends toward a proximal side and about said equiradial shaft portion.20. A medical guide wire as defined in claim 18, wherein said helicalcoil includes an equiradial coil end disposed to extend from saiddiameter decreasing coil portion to said guide wire tip; said coreelongated component includes an equiradial shaft end disposed to extendfrom said tapered shaft portion and inside said equiradial coil end. 21.A medical guide wire as defined in claim 2, wherein said helical coil isso disposed that a space of a predetermined thickness is defined aboutsaid core elongated component in a range offset from said middleconnector.
 22. A medical guide wire as defined in claim 21, wherein saidhelical coil includes an equiradial coil end disposed to extend fromsaid diameter decreasing coil portion to said guide wire tip; said coreelongated component includes an equiradial shaft end disposed to extendfrom said tapered shaft portion and inside said equiradial coil end.